This proposal is for an epidemiologic study of high blood pressure in young people in Tecumseh, Michigan. It consists of cross-sectional and longitudinal studies of persons less than 20 years of age at the time of their first examination in 1959-1960 or 1962-1965. Follow-up and re-examination is proposed for 1976-77. The principal objective of the study is to relate multiple physical, physiological and socioeconomic findings at the initial examination to blood pressure level, at the same time and 12-18 years later. At the initial examination personal, demographic, and physiologic characteristics and familial relationships were ascertained as well as findings from examination of the cardiovascular system. Examples of these characteristics are age, sex, height, weight, skinfold thickness, heart rate, levels of blood glucose, serum cholesterol, uric acid and hematocrit. Education, occupation, income, and health of the mother during her pregnancy with the index and his siblings were also recorded. Study subjects have been identified as individuals and as members of families; analyses will seek relationships between blood pressure and potential risk factors in individuals as well as patterns of familial aggregation and familial resemblance. For those subjects who were examined twice, in 1959-1960 and 1962-1965, longitudinal analyses will be done with existing data for the relatively short average time interval of four years. Change in findings between the first and second examinations will also be related to the findings in 1976-1977. Risk factors for high blood pressure will be identified and the predictive ability of risk factors acting singly and in combination will be assessed.